Resilient container and method of sealing it



J y 1933- B. c. EBERHARD 1,918,524

RESILIENT CONTAINER AND METHOD OF SEALING IT Original Filed March 20,1929 gwpentoz Boyd C. Eberhard i v Patented July 18, 1933 morn-o. Emmi),or axnou, om nss'muoa 'rofrnneoonym m a noun comm, or men, onio, acoaroaarrou or 'onro 8 m c mm a amnan or simmer Continuation ofapplication Serla1No.348,451, filed March 20', 1929'.

'SerialNo.462,B55:

. .This invention relates to air containers ,which are formed ofrubber,and it has articular relation to pneumatic articles havmg valvestructures secured in the walls thereof, and to. methodso f isecuringsuch structures in'position, This application is av continuation of myapplication Serial No. 348,451, filed March 20, 1929. a

The object ofthe invention is to provide a" fluid tight seal between thebase portion of air valves or other metallic bodies and the walls ofrubber air containers throughwhic [the extend. a t

, eretofore, muchedifiiculty has been ex-- perienced in obtaining apermanent fluidtight seal about the metallic bodieswhich extendedthrough the walls of such flexible containers as airbags employed in thevulcanization of tires and inner. tubes used to inflate pneumatictires.-This was partmularly true in cases where the containers were v sub ectedto such relativelyvhigh temperamitting fiuid to escape. Vhenthisioccurred container, whereby to obtain a permanent seal therebetweenwhich isnot destroyed by tures and pressures as vthose encountered inthe. use of inner tubes for truck t1res or in airbags employed in thevulcanization of 'pneumatic tires. Heat generated about the metallicbody apparently softened I and weakened eventhe vulcanized r ubber,vthuscausing it to'crack or tear or to tend-to spread out'under the pressurecreated by theclamping action of the base portion ofthe valve and thecoacting bridge plate, thereby .per-

it became necessary to tighten up. the bridge plate. The latteroperation could only be accomplished after removal of the tube from thewheel, and hence involved considerable labor. 1

.. One feature of the invention involves the provision. of a patch ofveryslow ouring,

a tacky semi-plastic,isemhelastic or dough-like compoundbetween the baseof the metallic body and the walls ofthe finished vulcanized theeflectsof heat upon the container, either during or after, itsvulcanization,

- For a better understanding ,oftheinvention, referencemay. now be hadto theaccompanying drawing,- forrning a part of the V specification, ofwhich a j r ,Figal is'a fragmentaryplan view ofa portion of an innertube wall embodying a valve structure which is sealed according to theinvention; and

Tliil application flld June 81, 1980.

2 is a view partially in cros's-section and partially in elevation of.theembodiment of the invention disclosed 'inFig. 1,;

i In practicing the invention, an inner tube or similar container5,icomposed entirely of vrubber, or; at; least 1 comprlsing rubberizedmaterial, either with or without a valve patch 6, is pierced to receivethe innerportion of a valve stem '7 of conventional design. It is to beunderstood that the wallsiof the container, 1 apart from the patch 6,inthe finished article,

are composed of vulcanized, non plastic,'n'ontacky material which,in-airbags and inner tubes, is relatively; elastic. and, flexible, Inorder to secure the valvein position, the in her endof thevalvestemisformed with a flanged base 8, which isembedded within a patch of slow.curing semi-plastic, yisemielasticior dough-likegum material,9,that

adheres to the inner wall, of the container.

This material 9 is applied beforeathe container is vulcanized andremainsin a tacky,

dough-like condition even after beingsub- Jected to the heat forvulcanizing thecontainer. Thus the vulcanization of the eon tainerprovides a firm bond between it and the dough-like patch the finishedarticle. i

The stem 7 adj acent to the exterior side of the wall of the tube 5 basescrew-threaded portion 11 to r i a lamp g -12 which presses upon awasher or bridge plate "13, thereby securely clamping the portions ofthe tube wall adjacent the valve opening.

' The composition of'the patch 9 may-vary within "relatively widelimits, although it is essential that it retain its elasticity andplasticity throughout its normal life." In actual practiceit has beenfound that a rubber com- ;pound containing from 20 to '40 percentxofrubber and 40 to 60percent ofzinc oxide,fl-togeth'erfwithf a smallamount ofsulphur (1 to: 5 perlcent) satisfactory. Thefollow'ing {is aspecific example of a formula 0t a compound which insures excellent1te'sults :,:;'"L

' Material prepared in accordance with this formula is spreadwhile greenor uncured and is partially cured or semi-cured by theheat I requiredfor vulcanizingzthe tube .or other article to which the inventionisapplied'.

"no I l 50 character.

The relatively large proportion of pigment employed in this compoundinsures a material which does not flow under the tempera- "turesordinarily encountered in such rubber containers as inner tubes fortruck tires and airbags. Furthermore, the material is extremely slowcuring and never loses its semiplastic, semi-elastic -dough-likecharacter throughout its normal period of use. In the I claims I havereferred to this material as a being permanently semi-plastic,semi-elastic, tacky or dough-like in character and'it will be understoodthat'the term permanently means throughout the normal period of use ofthe material. It is also of asufiiciently tacky.

nature to adhere not 'onl to the inner surface of the containers in wich it is employed, but it also tends to adhere to the metal itself.Because of its plasticity, elasticity and-tacki- 0 ness, the compoundreadily yields to deforming stresseswhichare set up when the wall of thecontainer tends to diminish in thickness, or to tear about the valvestem. Therefore, a perfect seal is maintained about the I latter at alltimes,even though the rubberin the wall of the tube may tend to flowaway fromthe' valve seat. p

The composition of the tubewall of course may be varied so long as ithas sufficient tensile strength and firmness for the purpose for whichit is desi ned. The following is a specific examplelo I a materialapplicable for the manufacture of vehicle tire inner tubes:

' Smoked sheet rubber 100 Zinc oxide -g. 92. 5 Carbon black .6 Stearicacid p .7 Su1phur 3. 5 Diphenylguanidine 7 Phenyl beta naphthylamine 5In the above formula, the relative propertions'of the severalingredients ma be varled. to meet specific requirements. A so, certam ofthematerials such as the activator, stearic acid the accelerator,diphenylguanidine and the antioxidant phenyl beta naphthylamine v may bereplaced by other substances of like Conventional methods are em- Iployed in curingor vulcanizing tubes or airbags prepared according tothis specification.

Although the invention has been *specifically described as applied tothe valve stems .55 of inner tubes, it is to be understood that it 1'iicapable of much wider application than t at. maybe used for sealingabout the bases of the valves of airbags employed in the vul-- -0canization of tires, or it may be employed about the couplings-of hosewhere the latter are subjected to relatively high heats and fluidpressures. In the preceding description, the term ferred forms which theinvention may the invention" or from 'ing therethrough, avalve seatportion upon the inner end of the valve stem, and a patch end of thevalve, and a patch 0 The soft plastic material disclosednon-plastic isemployed to indicate a material which at normal atmospheric temperaturesdoes not tend to flow and which does not permanently retain ordinarydeformations to which it may be subjected in use.

-Although I have disclosed only, the preassume, it will be apparent tothose skilled in the art that the invention is not so limited but thatvarious-modifications may bemade therein without departing-from thespirit of the. scope of "the.

appended claims.

' WhatIclaim is! a 1. Anon-plastic rubber container for fluid 8 underpressure having a valve'stem extendof' permanently semi-plastic,semi-elastic, tacky material disposed between the seat" portion and thewalls' of the container.

- 2. A rubber container for fluid under compression having a valve stem"extending therethrough, a seat portion 11 on the inner Eslow curing,semi-plastic, dough-like rubber compound consisting of 20 to 40 percentrubber, 40 to 60 percent zinc oxide and 1 to '5 percent sulphur disposedbetween the seat portion and theinner side of the wall of the container.

3. A non-plastic rubber inner tube for yehide tires having a valve stemextending therethrough, a seat-portion u on the inner end of the valve,and apatch o permanently semi-plastic, tacky dough-like materialdisposed between the face of the seat portion and the inner side of thewall of the tube. I

4. A composite body comprising-two portionsof metal, a sheet of rubberdisposed between'and held under compression'by the v bodies, and a patchof permanently semiplastic, semi-elastic, dough-like rubber compounddisposed between one ofthe portions and the-sheet. w

5. Aco'mposite body comprising a portion of cured, elastic non-plasticrubber clamped between two portions of metah'the pointsiof contactbetween the rubber and the metal being sealed bythe'application ofcoatings I I I of semi-plastic, semi-elastic, tacky dough-

